1. Field of the Invention
The present invention relates to an image forming apparatus, a method for controlling an image forming apparatus, and a program.
2. Description of the Related Art
In recent years, a use of a mass-storage media such as a hard disk has been becoming crucial to an electrophotographic image forming apparatus, due to an increase in the program size as a result of the multifunctionalization, and an increase in the storage area for output and storage of high-resolution and high-gradation images. Accordingly, the importance of a hard disk has been significantly growing, and ever-increasing print speed and accessing of a multifunctionalized application to a hard disk are affecting the functionality and usability of the apparatus.
However, generally, a hard disk is prone to breakage. Once a tiny damage is made on the surface of a hard disk, that area turns into a so-called “bad sector”. Such a bad sector may be in a “write-abort” state, and data may not be able to be written thereon normally. Other examples of failures that may occur on a bad sector include inability of normal reading. In this case, the reading retrying operation may be repeated over and over, resulting in an extreme slowdown of the data reading speed.
Therefore, such a bad sector may not only impair the overall performance of the apparatus, but also even make a startup of the image forming apparatus impossible depending on the location of a bad sector. A bad sector may be generated during a manufacturing process of a recording media, and may also be generated during operation by a strong impact from the outside, such as a contact between a head and the media. Further, in some cases, a bad sector is in a completely unreadable and unwritable state, while in other cases, a bad sector is yet to become completely unreadable and unwritable but cannot be normally read or written by one operation so that the retry operation is repeated over and over as mentioned above. In such a case, a bad sector may be a major factor in a slowdown of the data access speed.
With the aim of reducing bad sectors and operation failures, hard disk manufacturers, personal computer (PC) manufacturers, and software development companies have proposed various approaches. For example, device information called “Self-Monitoring, Analysis and Reporting Technology (SMART) information” including the number of alternative sectors, an OFF/ON count, a power-on time, and a seek time of a hard disk is stored in a memory or another storage. There is proposed the function of recommending replacement of a hard disk when these values reach predetermined certain values. Especially, the above-mentioned number of alternative sectors which are provided as an alternative in case of occurrence of a bad sector gains importance as a determination parameter for replacement of a hard disk.
However, since the criterion for determining a bad sector is established by hard disk manufacturers on their own accord, the following problem exists. For example, even if a sector slows down the transfer rate which is fatal to an image forming apparatus using the hard disk, this sector is not determined as a bad sector as long as it can be read by retrying operations within a certain time or a certain retrying count. Therefore, in this case, alternating of sector does not occur, and therefore the number of alternative sectors is not incremented. Further, an analysis of hard disks collected as faulty products from the market has revealed that most of them do not have a bad sector. In addition, in reality, most of them are determined as normal products even when the normal/faulty determination function is used which is a function of the SMART. In other words, the SMART information based on the manufacturers own rules is not sufficiently accurate, and a unique criterion should be established for an image forming apparatus using a hard disk. Under this circumstance, when the hard disks are further analyzed, it may become apparent that the transfer rates of some sectors are significantly reduced in many cases.
One conventional technique for solving this problem is a system which recommends replacement of a hard disk to a user before occurrence of an abnormal operation which might cause a slowdown of the access speed, by monitoring the access time of the hard disk (Japanese Patent Application Laid-Open No. 2004-165741). Another conventional technique is a system which monitors the access time of a hard disk, and sets a relevant area as a use prohibition area if the access speed is reduced to be lower than a preset value (Japanese Patent Application Laid-Open No. 2002-116931).
However, these conventional techniques do not discuss a method for measuring an access time of a hard disk, and a method for detecting an abnormal operation. According to the abnormal operation detection method in the above-mentioned conventional techniques, a certain value is preset, and an error cannot be detected until the criterion parameter comes down to a level low enough to affect the system, which leads to a problem in that the machine may suddenly break down. This problem becomes notable especially when a hard disk is replaced with a hard disk having a higher data access speed (for example, a hard disk manufactured by a different manufacturer or a hard disk of a different generation).